Numerical analysis of spot welds in sheet metal structures exposed to mechanical shock and vibration loading

Automobilska industrija jedna je od najvećih svjetskih industrija koja godišnje proizvodi otprilike 50 milijuna vozila. U novije vrijeme se, zbog ograničenja emisija ispušnih plinova te zahtjeva za povećanjem sigurnosti cestovnog prometa, ali i zahtjeva kupaca, suvremena autoindustrija suočava s izazovima smanjenja mase vozila, poboljšanja ekonomičnosti potrošnje goriva te optimiranja u svrhu povećanja kompatibilnosti tijekom sudara. Elektrootporno točkasto zavarivanje je najzastupljeniji postupak spajanja metalnih limova u autoindustriji, a zavar nastaje uslijed topline koja se razvija prolaskom struje kroz elektrode te otpora materijala koji se zavaruje. Dakle, točkasti zavar nastaje kao rezultat kompleksnog međudjelovanja topline, pritiska elektroda i naglih faznih pretvorba u materijalu. Budući da točkasti zavar predstavlja geometrijski i materijalni diskontinuitet, oko zavarenog spoja javlja se koncentracija naprezanja, što ima negativan utjecaj na pojavu pukotina uslijed cikličkih opterećenja te na integritet konstrukcije tijekom dinamičkih opterećenja, tj. sudara. Nadalje, numerička analiza pomoću metode konačnih elemenata te razvoj metoda za proračun zavara na temelju sila omogučuju brz i jednostavan proračun točkasto zavarenih spojeva uslijed cikličkih i dinamičkih opterećenja, čime se smanjuju troškovi i vrijeme eksperimentalnih ispitivanja u fazi izrade prototipa i konstruiranja. Stoga je cilj ovog diplomskog rada razviti numeričke procedure za proračun točkasto zavarenih spojeva uslijed cikličkih opterećenja s konstantnim amplitudama i stohastičkih uzbuda te uslijed dinamičkog šoka.Occupant safety, weight reduction, fuel efficiency and vehicle crashworthiness remain the most challenging design objectives of the modern automotive industry. Recent improvements in sheet metal joining processes and the use of advanced high strength steels have increased fuel-efficiency and enhanced vehicle durability, as well as the integrity of passenger compartment, simultaneously increasing weight reduction. Resistance spot welding is the most widely used metal joining process in automotive industry intended for joining of light gauge overlapping metal sheets. Although resistance spot welding includes complex interaction between mechanical loading, heating generated by the electric current and rapid microstructural transformations, compared to other joining processes, resistance spot welding is fast, easily automated and does not require the additional filler material. Since the material heterogeneity and geometric discontinuity around the weld nugget circumference cause stress concentration, spot-welded components are prone to premature failure under fatigue and crash loading conditions. Hence, it is crucial to understand the welded region microstructure and the mechanical behavior of spot-welded joints to balance competing design objectives and thus enhance vehicle durability and crashworthiness. In recent times numerical analyses have had a major impact on design optimization and cost reduction of full-scale experiments during prototype testing. Moreover, various numerical methods have been proposed to evaluate the fatigue strength of spot welds under constant amplitude loading. Generally, the fatigue analysis of spot-welded joints is classified into stress-based and force-based approaches. In comparison with the stress-based method, the force-based approach offers a quick solution and an accurate fatigue life estimation. Therefore, one of the objectives of the conducted research was to evaluate the existing methods for the fatigue analysis of spot-welded structures under constant amplitude loading and to study the effect of geometric characteristics on the fatigue behavior of spot-welded specimens. However, vehicle components are seldom subjected to the constant amplitude cyclic loading, thus the method of random vibration fatigue life prediction for spot-welded structures is evaluated. Finally, quasi-static damage analysis of spot-welded specimens is performed to evaluate the coupled force-based damage initiation criterion, which captures the complex behavior of spot-welded joints under general loading conditions, yet greatly simplifying the analysis

Intelectual Property Rights, Plant Breeding and Nursery Practice

Termin Cultivar je skraćenica od engleskih riječi cultivated što znači kultivirana i variety što znači vrsta. Cultivar nastaje oplemenjivanjem. U povijesti čovječanstva stvarani su brojni cultivari žitarica, voća, povrća, industrijskog bilja, ukrasnog bilja i šumskog drveća. Novi proizvodi ili novi cultivari prodaju se na tržištu zbog zarade, a zaštita cultivara kao intelektualnog vlasništva osigurava da dio zarade dobije inovator, odnosno oplemenjivač. Cultivar može biti u formi klona ili u formi poboljšanog sjemena, pa se tako na meću i dvije karakteristične strategije: zaštita intelektualnog vlasništva ople menjivača (Plant Breeder’s Right, skraćeno PBR) i zaštita komercijalnog imena (Trade Mark).The term Cultivar is an abbreviation of the English words cultivated and variety. A Cultivar is the result of plant breeding. In the history of man numerous Cultivars have been created of cereal grains, fruit, vegetables, industrial plants, ornamental plants and forest trees. New products or new Cultivars are sold on the market for profit. Protection of the Cultivar as intellectual property ensures a part of the profit goes to the innovator, i.e. the plant breeder. A Cultivar can be in the form of a clone or in the form of improved seed, and therefore two characteristic strategies are deployed: protection of the intellectual ownership of the plant breeder (Plant Breeder’s Right, PBR) and protection of the commercial name (Trade Mark, TM)

Inshore capture-based tuna mariculture impact on Posidonia oceanica (L.) Delile meadows in the area of Fulija Islet (Central Adriatic Sea)

Kartiranje i praćenje stanja morske cvjetnice Posidonia oceanica u hrvatskom dijelu Jadranskog mora pokazuju značajno smanjenje gustoće livada u područjima pod utjecajem priobalnog kaveznog uzgoja tune. Predstavljeni su rezultati istraživanja područja u blizini otočića Fulije koje je pod utjecajem uzgajališta tune. Ovaj rad dokazuje da su obogaćivanje nutrijentima i rizik od eutrofikacije veliki problem ovog područja. Akvakulturni otpad izvor je onečišćenja nutrijentima koje stimulira cvjetanje fitoplanktona i zajednica alga, te obogaćuje sediment organskom tvari. Analizirani su stanje i gustoća livada vrste Posidonia oceanica pod utjecajem uzgajališta tune (otočić Fulija) i izvan njega (dvije kontrolne stanice na otoku Ižu i otočiću Mrtovnjaku). Istraživane su fizikalno-kemijske i biološke varijable u svrhu procjene utjecaja tunogojilišta na litoral u blizini otočića Fulije. Pored bioloških i standardnih osnovnih kemijskih parametara, poput koncentracije otopljenih nutrijenata, ispitani su i utjecaj ribogojilišta na distribuciju otopljenog organskog ugljika (DOC) te površinski aktivnih tvari (SAS). Pronađene su značajne razlike između koncentracije nutrijenata među istraživanim postajama pod utjecajem uzgajališta tune (otočić Fulija) i onima izvan njega (kontrolne postaje). Mukozni agregati bentoskih alga na livadama posidonije primijećeni su tijekom proljeća i ljeta. Broj izdanaka livada vrste P. oceanica smanjen je na postajama u blizini uzgajališta tune, što potvrđuje da aktivnosti ribogojilišta značajno utječu na okolne livade.Mapping and monitoring of the seagrass Posidonia oceanica in Croatian part of the Adriatic Sea showed significant decline in meadows density in the area influenced by inshore capture-based tuna aquaculture. The results of Posidonia meadows survey in the area of Fulija Islet, which are under the influence of tuna farms, are presented. This paper proves that nutrient enrichment and the risk of eutrophication is a significant issue in this area. Aquaculture wastes are a source of nutrient pollution and stimulate blooms of phytoplankton and algae population, as well as organic matter enrichment in the sediment. The condition and density of Posidonia oceanica meadows under the influence of tuna farms (at Fulija Islet) and out of its reach (two control stations at Iž Island and Mrtovnjak Islet) have been analyzed. Physico-chemical and biological variables have been examined in order to evaluate the impact of a tuna farm on the littoral near Fulija Islet. Besides biological and standard basic chemical parameters, such as the concentration of dissolved nutrients, the influence of fish farming on the distribution of dissolved organic carbon (DOC) and surface active substances (SAS) in the water column were also investigated. Significant differences were found between nutrient concentrations among the investigated stations under the influence of tuna farm (Fulija Islet) and out of its reach (control stations). The mucous aggregates of the benthic algae were observed during the spring and summer on the P. oceanica meadows. Shoot density of the P. oceanica meadows decrease at the stations close to the tuna farm, which confirms that the tuna farm activity strongly affects the surrounding meadows

Frontal Attack or Retrograde: C Croatian Military Terminology Confronting Anglo-American Terminological Influx

With the accession of Croatia to NATO, Croatian military terminology was confronted with a vast and complex terminological pool in English, for which Croatian equivalents had to be developed. This paper aims to address and investigate both latent and conspicuous mirroring of English term-formation patterns at all linguistic levels, as well as calqueing as a mechanism for creating Croatian equivalents. The research was undertaken on a corpus-verified excerpt of terms that were subjected to terminological analysis. Prima facie observations confirmed the efforts of subject matter experts to develop contemporary Croatian military terminology using Croatian language material. However, multiple criteria revealed the sample was debatable, both from the perspective of the standard Croatian language and of terminological principles. The research demonstrated that Croatian (terminological) term formation – as the most desirable method of term formation – is significantly underrepresented and dominated by latent linguistic borrowing (calques) and multiword term units. Because multiword terms constitute the most prevalent subgroup of terms today, they were given additional consideration, especially as Anglo-American structures and patterns are most closely emulated at this level of term formation. Anglo-American formation patterns frequently take priority, typically under the pretext of their alleged precision and transparency, despite the Croatian language substantial inherent term-formation potential. To systematize military terminology and introduce stability into the conceptual system, the author deemed it beneficial to go beyond the merely descriptive level of research and render solutions for terminological gaps or the terminology requiring revision and normative preference by undertaking concrete normative interventions and providing practical paradigmatic models. Finally, the rendered solutions were designed to both catalyze future interventions in Croatian military terminology and revise the current one

Numerical analysis of spot welds in sheet metal structures exposed to mechanical shock and vibration loading

Automobilska industrija jedna je od najvećih svjetskih industrija koja godišnje proizvodi otprilike 50 milijuna vozila. U novije vrijeme se, zbog ograničenja emisija ispušnih plinova te zahtjeva za povećanjem sigurnosti cestovnog prometa, ali i zahtjeva kupaca, suvremena autoindustrija suočava s izazovima smanjenja mase vozila, poboljšanja ekonomičnosti potrošnje goriva te optimiranja u svrhu povećanja kompatibilnosti tijekom sudara. Elektrootporno točkasto zavarivanje je najzastupljeniji postupak spajanja metalnih limova u autoindustriji, a zavar nastaje uslijed topline koja se razvija prolaskom struje kroz elektrode te otpora materijala koji se zavaruje. Dakle, točkasti zavar nastaje kao rezultat kompleksnog međudjelovanja topline, pritiska elektroda i naglih faznih pretvorba u materijalu. Budući da točkasti zavar predstavlja geometrijski i materijalni diskontinuitet, oko zavarenog spoja javlja se koncentracija naprezanja, što ima negativan utjecaj na pojavu pukotina uslijed cikličkih opterećenja te na integritet konstrukcije tijekom dinamičkih opterećenja, tj. sudara. Nadalje, numerička analiza pomoću metode konačnih elemenata te razvoj metoda za proračun zavara na temelju sila omogučuju brz i jednostavan proračun točkasto zavarenih spojeva uslijed cikličkih i dinamičkih opterećenja, čime se smanjuju troškovi i vrijeme eksperimentalnih ispitivanja u fazi izrade prototipa i konstruiranja. Stoga je cilj ovog diplomskog rada razviti numeričke procedure za proračun točkasto zavarenih spojeva uslijed cikličkih opterećenja s konstantnim amplitudama i stohastičkih uzbuda te uslijed dinamičkog šoka.Occupant safety, weight reduction, fuel efficiency and vehicle crashworthiness remain the most challenging design objectives of the modern automotive industry. Recent improvements in sheet metal joining processes and the use of advanced high strength steels have increased fuel-efficiency and enhanced vehicle durability, as well as the integrity of passenger compartment, simultaneously increasing weight reduction. Resistance spot welding is the most widely used metal joining process in automotive industry intended for joining of light gauge overlapping metal sheets. Although resistance spot welding includes complex interaction between mechanical loading, heating generated by the electric current and rapid microstructural transformations, compared to other joining processes, resistance spot welding is fast, easily automated and does not require the additional filler material. Since the material heterogeneity and geometric discontinuity around the weld nugget circumference cause stress concentration, spot-welded components are prone to premature failure under fatigue and crash loading conditions. Hence, it is crucial to understand the welded region microstructure and the mechanical behavior of spot-welded joints to balance competing design objectives and thus enhance vehicle durability and crashworthiness. In recent times numerical analyses have had a major impact on design optimization and cost reduction of full-scale experiments during prototype testing. Moreover, various numerical methods have been proposed to evaluate the fatigue strength of spot welds under constant amplitude loading. Generally, the fatigue analysis of spot-welded joints is classified into stress-based and force-based approaches. In comparison with the stress-based method, the force-based approach offers a quick solution and an accurate fatigue life estimation. Therefore, one of the objectives of the conducted research was to evaluate the existing methods for the fatigue analysis of spot-welded structures under constant amplitude loading and to study the effect of geometric characteristics on the fatigue behavior of spot-welded specimens. However, vehicle components are seldom subjected to the constant amplitude cyclic loading, thus the method of random vibration fatigue life prediction for spot-welded structures is evaluated. Finally, quasi-static damage analysis of spot-welded specimens is performed to evaluate the coupled force-based damage initiation criterion, which captures the complex behavior of spot-welded joints under general loading conditions, yet greatly simplifying the analysis

SUPOSTAVLJANJE HRVATSKOGA VOJNOG NAZIVLJA DVAJU PRIJELOMNIH RJEČNIKA 19. STOLJEĆA

The aim of this paper was to revisit and shed new light on the generally accepted view that the impact of German-Illyrian dictionary (Nĕmačko-ilirski slovar) by Ivan Mažuranić and Jakov Užarević of 1842 on Bogoslav Šulek’s German-Croatian dictionary (Nĕmačko-hrvatski rĕčnik) of 1860 was decisive and indispensable in many aspects, nothing if not a fundamental dictionary in Šulek’s work. This research was undertaken to put to the test this assertion by investigating more in depth the military subcorpora of both dictionaries, especially bearing in mind Šulek being the founding father of Croatian military terminology. The primary goal was to excerpt Croatian military terminology from both dictionaries in order for them to be mutually juxtaposed and made subject to a combination of quantitative and qualitative research. In terms of quantitative outcomes, we tried to detect and register German headwords and their corresponding Croatian equivalents to the most comprehensive extent possible, having produced two parallel subcorpora. The results of the correlational analysis prompted us to re-evaluate the proportions of Mažuranić and Užarević’s influence on Šulek. In terms of qualitative results, the research primarily outlined the spectrum of word-formation methods in both dictionaries and linguistic purism tendencies. In the final analysis, it can be reasonably assumed that Šulek did resort to the German-Illyrian dictionary as one of his valuable sources but in all likelihood as an auxiliary one, let alone a fundamental one.Cilj je ovoga istraživanja preispitati i baciti novo svjetlo na prošireni stav u literaturi kako je utjecaj Nĕmačko-ilirskoga slovara Ivana Mažuranića i Jakova Užarevića iz 1842. na Nĕmačko-hrvatski rĕčnik Bogoslava Šuleka iz 1860. bio u mnogočemu presudan i neizostavan. Štoviše, da je bio temeljnim rječnikom Šulekova rada. Ovim se radom ta tvrdnja dublje istražuje na vojnom nazivlju obaju rječnika, a posebno imajući na umu kako se Bogoslava Šuleka smatra utemeljiteljem hrvatskog vojnog nazivlja. Primarni je cilj bio ekscerpirati vojno nazivlje obaju rječnika kako bi ga se međusobno supostavilo i podvrgnulo kombinaciji kvantitativne i kvalitativne raščlambe. U smislu kvantitativnih rezultata, nastojalo se u što iscrpnijoj mjeri pronaći i zabilježiti njemačke polazne natuknice i njihove hrvatske ekvivalente iz čega su proizišla dva paralelna potkorpusa. Rezultati suodnosne raščlambe znakovito su rasvijetlili dosege utjecaja Mažuranić-Užarevićeva rječnika na Šulekov rječnik. U smislu kvalitativnih rezultata, istraživanjem se izložila u glavnim crtama prije svega razrađenost tvorbenih obrazaca obaju rječnika i njihova puristička nastojanja. U konačnici, čini se opravdano pretpostaviti kako Šulek jest posezao za Mažuranić- Užarevićevim rječnikom kao jednom od svojih vrijednih izvora, no po svoj prilici kao pomoćnim rječnikom, a daleko od toga kao temeljem svojega rječnika

Biometry and distribution of snipefish, Macroramphosus scolopax(Linnaeus, 1758), in the Adriatic Sea

Specimens of the snipefish, Macroramphosus scolopax (Linnaeus, 1758), from the middle and southern Adriatic were biometrically analyzed during the demersal communities research project, MEDITS. The specimens (n = 103) were caught at depths deeper than 100 m. Total length ranged 4.8-16.0 cm, with a mean of 9.45±2.796 cm. According to the length-weight relationship, positive allometric growth was established (b = 3.23)

Evaluating Regular Path Queries in GQL and SQL/PGQ: How Far Can The Classical Algorithms Take Us?

We tackle the problem of answering regular path queries over graph databases, while simultaneously returning the paths which witness our answers. We study this problem under the arbitrary, all-shortest, trail, and simple-path semantics, which are the common path matching semantics considered in the research literature, and are also prescribed by the upcoming ISO Graph Query Language (GQL) and SQL/PGQ standards. In the paper we present how the classical product construction from the theoretical literature on graph querying can be modified in order to allow returning paths. We then discuss how this approach can be implemented, both when the data resides in a classical B+ tree structure, and when it is assumed to be available in main memory via a compressed sparse row representation. Finally, we perform a detailed experimental study of different trade-offs these algorithms have over real world queries, and compare them with existing approaches

Internationalisms as (un)necessary terminological refuge in the military terminology

Istraživački interes u ovome radu usmjeren je na internacionalizme u hrvatskome vojnom nazivlju. U prvome se redu tematiziraju zastupljenost i geneza njihova naslojavanja u terminološkome sustavu te utjecaj engleskih leksičkih modela na daljnje oblikovanje hrvatskih istovrijednica internacionalizmima. Posebno se progovara o paušalnoj predodžbi da se hrvatsko vojno nazivlje u minimalnoj mjeri izgrađuje internacionalizmima (i općenito posuđenicama) te o izvanjezičnim utjecajima kroz povijest na njegovo oblikovanje. Nakon dijakronijsko-sinkronijskoga uvida u pripremljeni korpus sagledavaju se rezultati sraza hrvatskih predloženica i međunarodnih ustaljenica u jezičnoj praksi. Na kraju, predlaže se teorijski pristup daljnjoj izgradnji vojnoterminološkoga sustava internacionalizmima kao terminološkoga sustava sui generis, u simboličko-identitetskome smislu.This research seeks to address internationalisms in Croatian military terminology. The primary topic of discussion is their volume and genesis of their stratification in the terminological system, and the influence the English lexical models exert on further creation of Croatian equivalents by resorting to internationalisms. The paper particularly discusses the generalized notion that Croatian military terminology is to a minimal degree built by the use of internationalisms (loanwords in general). Furthermore, the research investigates the extra-linguistic factors that predestined its evolution and – after diachronic and synchronic insight into the prepared corpus – the results of the clash between native Croatian proposals and well-rooted internationalisms in language practice are examined. Bearing in mind that military terminology is – from symbolic and identity vantage point – a sui generis terminological system, a theoretical approach for its further and possible development by internationalisms is proposed